Battery power supply



FIG. 1 is a top, right, front isometric view showing my new design;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a right side view of FIG. 1;

FIG. 4 is a rear view of FIG. 1;

FIG. 5 is a left side view of FIG. 1;

FIG. 6 is a top view of FIG. 1; and,

FIG. 7 is a bottom view of FIG. 1. 

The ornamental design for a battery power supply, as shown and described. 